/*
 *  RFC 1321 compliant MD5 implementation
 *
 *  Based on XySSL: Copyright (C) 2006-2008  Christophe Devine
 *
 *  Copyright (C) 2009  Paul Bakker <polarssl_maintainer at polarssl dot org>
 *
 *  All rights reserved.
 *
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    * Neither the names of PolarSSL or XySSL nor the names of its contributors
 *      may be used to endorse or promote products derived from this software
 *      without specific prior written permission.
 *
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *  "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *  LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 *  FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *  OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 *  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 *  TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 *  PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
/*
 *  The MD5 algorithm was designed by Ron Rivest in 1991.
 *
 *  http://www.ietf.org/rfc/rfc1321.txt
 */

#include "netif/ppp/ppp_opts.h"
#if PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_MD5

#include "netif/ppp/polarssl/md5.h"

#include <string.h>

/*
 * 32-bit integer manipulation macros (little endian)
 */
#ifndef GET_ULONG_LE
#define GET_ULONG_LE(n, b, i)                                                  \
  {                                                                            \
    (n) = ((unsigned long)(b)[(i)]) | ((unsigned long)(b)[(i) + 1] << 8) |     \
          ((unsigned long)(b)[(i) + 2] << 16) |                                \
          ((unsigned long)(b)[(i) + 3] << 24);                                 \
  }
#endif

#ifndef PUT_ULONG_LE
#define PUT_ULONG_LE(n, b, i)                                                  \
  {                                                                            \
    (b)[(i)] = (unsigned char)((n));                                           \
    (b)[(i) + 1] = (unsigned char)((n) >> 8);                                  \
    (b)[(i) + 2] = (unsigned char)((n) >> 16);                                 \
    (b)[(i) + 3] = (unsigned char)((n) >> 24);                                 \
  }
#endif

/*
 * MD5 context setup
 */
void md5_starts(md5_context *ctx) {
  ctx->total[0] = 0;
  ctx->total[1] = 0;

  ctx->state[0] = 0x67452301;
  ctx->state[1] = 0xEFCDAB89;
  ctx->state[2] = 0x98BADCFE;
  ctx->state[3] = 0x10325476;
}

static void md5_process(md5_context *ctx, const unsigned char data[64]) {
  unsigned long X[16], A, B, C, D;

  GET_ULONG_LE(X[0], data, 0);
  GET_ULONG_LE(X[1], data, 4);
  GET_ULONG_LE(X[2], data, 8);
  GET_ULONG_LE(X[3], data, 12);
  GET_ULONG_LE(X[4], data, 16);
  GET_ULONG_LE(X[5], data, 20);
  GET_ULONG_LE(X[6], data, 24);
  GET_ULONG_LE(X[7], data, 28);
  GET_ULONG_LE(X[8], data, 32);
  GET_ULONG_LE(X[9], data, 36);
  GET_ULONG_LE(X[10], data, 40);
  GET_ULONG_LE(X[11], data, 44);
  GET_ULONG_LE(X[12], data, 48);
  GET_ULONG_LE(X[13], data, 52);
  GET_ULONG_LE(X[14], data, 56);
  GET_ULONG_LE(X[15], data, 60);

#define S(x, n) ((x << n) | ((x & 0xFFFFFFFF) >> (32 - n)))

#define P(a, b, c, d, k, s, t)                                                 \
  {                                                                            \
    a += F(b, c, d) + X[k] + t;                                                \
    a = S(a, s) + b;                                                           \
  }

  A = ctx->state[0];
  B = ctx->state[1];
  C = ctx->state[2];
  D = ctx->state[3];

#define F(x, y, z) (z ^ (x & (y ^ z)))

  P(A, B, C, D, 0, 7, 0xD76AA478);
  P(D, A, B, C, 1, 12, 0xE8C7B756);
  P(C, D, A, B, 2, 17, 0x242070DB);
  P(B, C, D, A, 3, 22, 0xC1BDCEEE);
  P(A, B, C, D, 4, 7, 0xF57C0FAF);
  P(D, A, B, C, 5, 12, 0x4787C62A);
  P(C, D, A, B, 6, 17, 0xA8304613);
  P(B, C, D, A, 7, 22, 0xFD469501);
  P(A, B, C, D, 8, 7, 0x698098D8);
  P(D, A, B, C, 9, 12, 0x8B44F7AF);
  P(C, D, A, B, 10, 17, 0xFFFF5BB1);
  P(B, C, D, A, 11, 22, 0x895CD7BE);
  P(A, B, C, D, 12, 7, 0x6B901122);
  P(D, A, B, C, 13, 12, 0xFD987193);
  P(C, D, A, B, 14, 17, 0xA679438E);
  P(B, C, D, A, 15, 22, 0x49B40821);

#undef F

#define F(x, y, z) (y ^ (z & (x ^ y)))

  P(A, B, C, D, 1, 5, 0xF61E2562);
  P(D, A, B, C, 6, 9, 0xC040B340);
  P(C, D, A, B, 11, 14, 0x265E5A51);
  P(B, C, D, A, 0, 20, 0xE9B6C7AA);
  P(A, B, C, D, 5, 5, 0xD62F105D);
  P(D, A, B, C, 10, 9, 0x02441453);
  P(C, D, A, B, 15, 14, 0xD8A1E681);
  P(B, C, D, A, 4, 20, 0xE7D3FBC8);
  P(A, B, C, D, 9, 5, 0x21E1CDE6);
  P(D, A, B, C, 14, 9, 0xC33707D6);
  P(C, D, A, B, 3, 14, 0xF4D50D87);
  P(B, C, D, A, 8, 20, 0x455A14ED);
  P(A, B, C, D, 13, 5, 0xA9E3E905);
  P(D, A, B, C, 2, 9, 0xFCEFA3F8);
  P(C, D, A, B, 7, 14, 0x676F02D9);
  P(B, C, D, A, 12, 20, 0x8D2A4C8A);

#undef F

#define F(x, y, z) (x ^ y ^ z)

  P(A, B, C, D, 5, 4, 0xFFFA3942);
  P(D, A, B, C, 8, 11, 0x8771F681);
  P(C, D, A, B, 11, 16, 0x6D9D6122);
  P(B, C, D, A, 14, 23, 0xFDE5380C);
  P(A, B, C, D, 1, 4, 0xA4BEEA44);
  P(D, A, B, C, 4, 11, 0x4BDECFA9);
  P(C, D, A, B, 7, 16, 0xF6BB4B60);
  P(B, C, D, A, 10, 23, 0xBEBFBC70);
  P(A, B, C, D, 13, 4, 0x289B7EC6);
  P(D, A, B, C, 0, 11, 0xEAA127FA);
  P(C, D, A, B, 3, 16, 0xD4EF3085);
  P(B, C, D, A, 6, 23, 0x04881D05);
  P(A, B, C, D, 9, 4, 0xD9D4D039);
  P(D, A, B, C, 12, 11, 0xE6DB99E5);
  P(C, D, A, B, 15, 16, 0x1FA27CF8);
  P(B, C, D, A, 2, 23, 0xC4AC5665);

#undef F

#define F(x, y, z) (y ^ (x | ~z))

  P(A, B, C, D, 0, 6, 0xF4292244);
  P(D, A, B, C, 7, 10, 0x432AFF97);
  P(C, D, A, B, 14, 15, 0xAB9423A7);
  P(B, C, D, A, 5, 21, 0xFC93A039);
  P(A, B, C, D, 12, 6, 0x655B59C3);
  P(D, A, B, C, 3, 10, 0x8F0CCC92);
  P(C, D, A, B, 10, 15, 0xFFEFF47D);
  P(B, C, D, A, 1, 21, 0x85845DD1);
  P(A, B, C, D, 8, 6, 0x6FA87E4F);
  P(D, A, B, C, 15, 10, 0xFE2CE6E0);
  P(C, D, A, B, 6, 15, 0xA3014314);
  P(B, C, D, A, 13, 21, 0x4E0811A1);
  P(A, B, C, D, 4, 6, 0xF7537E82);
  P(D, A, B, C, 11, 10, 0xBD3AF235);
  P(C, D, A, B, 2, 15, 0x2AD7D2BB);
  P(B, C, D, A, 9, 21, 0xEB86D391);

#undef F

  ctx->state[0] += A;
  ctx->state[1] += B;
  ctx->state[2] += C;
  ctx->state[3] += D;
}

/*
 * MD5 process buffer
 */
void md5_update(md5_context *ctx, const unsigned char *input, int ilen) {
  int fill;
  unsigned long left;

  if (ilen <= 0)
    return;

  left = ctx->total[0] & 0x3F;
  fill = 64 - left;

  ctx->total[0] += ilen;
  ctx->total[0] &= 0xFFFFFFFF;

  if (ctx->total[0] < (unsigned long)ilen)
    ctx->total[1]++;

  if (left && ilen >= fill) {
    MEMCPY((void *)(ctx->buffer + left), input, fill);
    md5_process(ctx, ctx->buffer);
    input += fill;
    ilen -= fill;
    left = 0;
  }

  while (ilen >= 64) {
    md5_process(ctx, input);
    input += 64;
    ilen -= 64;
  }

  if (ilen > 0) {
    MEMCPY((void *)(ctx->buffer + left), input, ilen);
  }
}

static const unsigned char md5_padding[64] = {
    0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
    0,    0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0};

/*
 * MD5 final digest
 */
void md5_finish(md5_context *ctx, unsigned char output[16]) {
  unsigned long last, padn;
  unsigned long high, low;
  unsigned char msglen[8];

  high = (ctx->total[0] >> 29) | (ctx->total[1] << 3);
  low = (ctx->total[0] << 3);

  PUT_ULONG_LE(low, msglen, 0);
  PUT_ULONG_LE(high, msglen, 4);

  last = ctx->total[0] & 0x3F;
  padn = (last < 56) ? (56 - last) : (120 - last);

  md5_update(ctx, md5_padding, padn);
  md5_update(ctx, msglen, 8);

  PUT_ULONG_LE(ctx->state[0], output, 0);
  PUT_ULONG_LE(ctx->state[1], output, 4);
  PUT_ULONG_LE(ctx->state[2], output, 8);
  PUT_ULONG_LE(ctx->state[3], output, 12);
}

/*
 * output = MD5( input buffer )
 */
void md5(unsigned char *input, int ilen, unsigned char output[16]) {
  md5_context ctx;

  md5_starts(&ctx);
  md5_update(&ctx, input, ilen);
  md5_finish(&ctx, output);
}

#endif /* PPP_SUPPORT && LWIP_INCLUDED_POLARSSL_MD5 */
